The field of this invention relates to aromatic polyacyl compounds of polyphenyl structure suitable for use as a cross-linking agent for polymers containing hydroxyl or amine groups. The esters are useful as plasticizers for polyvinylchloride, heat transfer agents, hydraulic fluids, and insulating oils.
A new compound, hexa(meta-, para-carboethoxyphenyl)benzene has been prepared by the cyclotrimerization of 3,3' or 4,4'-dicarboethoxytolan, using dichlorobisbenzonitrilepalladium (II) as a catalyst. As is well known, cobalt octacarbonyl, bis(dibenzylidenacetone) palladium (0) and tri-isobutylaluminumtitanium tetrachloride have been effective for trimerization of hindered acetylenes. However, these catalysts were ineffective in this synthesis.
The preparation of benzene and substituted benzenes such as hexa-substituted benzenes from acetylenic compounds in the presence of specific solvents and catalysts is known in the art. For example, U.S. Pat. No. 2,723,299 teaches the preparation of benzene and styrene from acetylene and vinylacetylene in the presence of a solvent which can be benzene, acetonitrile or tetrahydrofuran and a catalyst such as triphenylphosphine nickel-dicarbonyl or with a co-catalyst compound of copper or mercury halogenide with trialkyl or triarylphosphine, or with a compound of a copper halide with ammonium salts, or with amine-hydrogen halogenide salts. U.S. Pat. No. 2,819,325 teaches the preparation of benzene and alkyl benzenes from 1-alkynes using a chromium oxide containing catalyst with a catalyst support comprising at least one member selected from the group consisting of silica, alumina, zirconia, titania and siliceous natural clays. Belgian Pat. No. 567,744 (CA53:16082d) teaches preparation of substituted benzene compounds by cyclization of mono- or di-substituted acetylene derivatives in the presence of metal carbonyls. Hexaphenylbenzene was prepared from tolan in presence of Fe(CO).sub.4. Phenylacetylene gave 1,2,3,5-tetraphenylbenzene. Hubel et al., Chem. Ber. 93, 103-15 (1960) (CA54:9841b) teach that mono- and di-substituted acetylenes heated in the presence of small amounts of metal carbonyl derivatives, with or without solvent, are converted to benzene derivatives. Phenylacetylene with [Co(CO).sub.4 ]Hg as catalyst gave hexaphenylbenzene. Similar reactions are taught in British Pat. No. 889,993 (CA58:1394h) and German Patent 1,142,867 (CA59:6317h). U.S. Pat. No. 2,980,741 teaches that divalent nickel hydrocarbon compounds are catalysts for polymerization of di-substituted acetylenes. Hexaphenylbenzene is prepared from diphenyl acetylene with a Grignard reagent as catalyst prepared from mesitylmagnesium bromide and nickel bromide. British Pat. No. 890,542 teaches preparation of tri- and hexa-substituted benzenes by trimerization of substituted acetylenes over a three-component catalyst. The three components of the catalyst system are (1) a titanium compound, a Fe(III) halide or a nickel compound; (2) a metal of Group IA, IIA, IIB or IIIA; (3) a halide of an element of Group IIB, IIIA, IVA or VA. Hexaphenylbenzene as well as other substituted benzenes are prepared. U.S. Pat. No. 3,073,873 teaches preparation of tetrasubstituted butadienes and related olefins by reacting a di-substituted acetylene with an organometallic compound. Tetraphenylbutadiene and alpha-ethyl-cis-stilbene are prepared from diphenylacetylene and triethylaluminum. U.S. Pat. No. 3,082,269 teaches preparation of hexa-substituted benzenes such as hexaphenylbenzene by contacting an acetylenic compound such as diphenylacetylene with a catalyst obtained by reacting a transition metal halide such as TiCl.sub.4 with an organometallic compound such as LiAl(C.sub.7 H.sub.15).sub.4. U.S. Pat. No. 3,129,243 teaches preparation of substituted benzene compounds such as hexaphenylbenzene from diphenylacetylene in the presence of a catalyst of iron tetracarbonyl. Preparation of other substituted benzene compounds such as hexa(para-chlorophenyl)benzene and 1,2-diphenyl-3,4,5,6 tetracarbomethoxybenzene are also taught.
In the prior art, it has also been known that the catalytic activity of particular catalysts has been remarkably specific. For example, Franzus et al. report, J.A.C.S., 81 (1959) p1514, that by regulating the ratio of triisobutylaluminum with titanium tetrachloride as cyclizing catalyst for acetylenic compounds, diphenyl acetylene can be trimerized to hexaphenylbenzene only between triisobutylaluminum: titanium tetrachloride ratios of 1:1 to 3:1. In other examples, triethylchromium (III) in tetrahydrofuran cyclizes tolan to hexaphenylbenzene, but also it contributes an ethyl group in a mixed condensation with tolan, yielding 1,2,3,4-tetraphenylbenzene in addition to the normal product, hexaphenylbenzene. Similarly, when tolan (diphenyl acetylene) was added to dimesitylnickel in tetrahydrofuran, small amounts of hexaphenylbenzene were obtained. However, when the order of addition was reversed, with mesitylmagnesium bromide being added to the mutually inert pair, nickel (II) bromide and tolan, the yield of hexaphenylbenzene rose steeply, J.A.C.S., 82 (1960) p6256. Similarly, the specificity of catalysts for cyclizing acetylenic compounds has been further documented; carbonyls of iron, cobalt and nickel (J.A.C.S., 83 (1961) p2944); bis-(benzonitrile)-palladium chloride in nonhydroxylic solvents such as benzene, chloroform and acetone (J.A.C.S., 84 (1962) p2330); nickel-carbonyl-phosphine complexes (J. Org. Chem., 27 (1962) p3930); noble metal halides (i.e., bis(benzonitrile) palladium chloride with methylphenylacetylene and dimethylacetylene (J.A.C.S., 92 (1970) p2276); dibenzylideneacetone-palladium (0) and -platinum (0) complexes (Chem. Communications (1971) p1604); cyclobutadienepalladium halide complexes (J. Organometal Chem., 26 (1971) 407-415).
The great number of methods for catalyzed cyclization of acetylenic compounds, however, to the best of our knowledge, has not led to the preparation of substituted hexaphenylbenzenes other than hexa(parachlorophenyl)benzene (U.S. Pat. No. 3,129,243). Accordingly, it is an object of this invention to provide a new group of aromatic polycarboxylic acids of hexa-substituted benzenes. Another object of this invention is to provide a process for making these acids. Another object of this invention is to provide a new polycarboxylic acid and ester, specifically hexa(meta-, para-carboxyphenyl)benzene, hexa(meta-, para-carboalkoxyphenyl)benzene, and hexa(meta-, para-carboaryloxyphenol)benzene and derivatives of these compounds. Other and further objects will be apparent from the following description.
The field of this invention accordingly has three aspects. First, it relates to novel compositions of matter that are hexa(meta-, para-carboxyphenyl)benzene compounds, second, to the method of preparing these compounds. Third, it relates to novel highly cross-linked insoluble compositions of these hexa(meta-, para-carboxyphenyl)benzene compounds with di- and polyfunctional compounds such as di- and polyamine and di- and polyhydroxy compounds, and to linear polymers available from the carboxyl compounds. The insoluble cross-linked compositions are useful as catalyst supports. Linear polymers containing the hexa-(meta-, para-carboxyphenyl)benzene moiety can be prepared by blocking all but two active carboxy sites, then preparing acyl chlorides from the acid and reacting the acyl chloride moieties with required mole ratios of amine or hydroxyl compounds.
These novel hexa(meta-, para-carboxyphenyl)benzene compounds (acids, acyl halides, simple esters, e.g., methyl, etc.) accordingly are desirable for use in the preparation of organic semiconductors, charge-transfer complexes, detergent builders, and as cross-linking agents for polymers.
The esters of these acids with monohydric alcohols containing 1 to 24 carbon atoms can be used as plasticizers for polyvinylchloride (PVC).
It has been found in accordance with this invention that hexa(meta-, para-carboxyphenyl)benzene compounds can be prepared by the cyclotrimerization of 3,3'- or 4,4'-dicarboalkoxytolan or 3,3'- or 4',4'-dicarboaryloxytolan using dichlorobisbenzonitrile-palladium (II) as a catalyst. The hexa(meta-, para-carboalkoxyphenyl)benzene or aryloxy compound can be saponified and converted to hexa(meta-, para-carboxyphenyl)benzene by acidification. Acyl halides can be prepared from the acid by replacing the hydroxyl group of the acid with a halogen. Accordingly, this invention relates to a new family of compositions of matter having the following structural formula ##STR1## wherein R is selected from the group consisting of hydrogen, alkyl and aryl moieties. When R is hydrogen, the --OR moiety can be replaced with a halogen moiety.